1. Field of the Invention
The present invention relates to a cushion attachment assembly and method for securing an inflatable cushion to a housing of an air bag module, and more particularly, to the attachment of an inflatable cushion to a housing including a tubular-type inflator.
2. Description of the Related Art
An inflatable air bag or cushion is a well known device for protecting an occupant of a vehicle which has been involved in a collision. The cushion is housed in an air bag module along with a reaction canister or housing and an inflator which upon actuation provides the gas to deploy or inflate the cushion.
The gas which deploys the cushion produces forces which can separate the cushion from its mounting. Thus, it is important to provide a cushion-housing attachment which is strong enough to absorb the high loads produced upon deployment and to prevent damage to the vehicle and/or passenger.
Previous methods of attaching an air bag to a module housing have included the use of a cushion attachment ring and fasteners, such as bolts or rivets, as disclosed in U.S. Pat. No. 5,234,227. The cushion must be fastened between the ring and the housing to avoid the concentration of load bearing stresses at the fasteners, which may be insufficient to prevent separation of the bag from the housing. It is difficult to assemble a cushion with a retainer ring and bolts and rivets because of the need to achieve and maintain the necessary alignment of the various fastener openings in the retainer ring, cushion and housing, see U.S. Pat. No. 5,193,846, assigned to the assignee of the present invention. Thus, it can be appreciated that attaching cushions by using fasteners and rings requires numerous parts and is labor intensive.
Another common method of attaching the cushion and housing uses rods which slide into the cushion and then in turn secure the cushion by sliding into a corresponding groove in the housing. Attachment of cushions using rods requires either a diffuser or metal covering structure which is used to aid in the insertion of the cushion, which contains the mounting rods, into the groove in the module housing, as fully described in U.S. Pat. No. 5,290,059, assigned to the assignee of the present invention. Without the use of the diffuser or metal covering, the cushion bunches up on the rod during insertion making assembly very slow and laborious.
The known fastening means fail to provide an inexpensive, strong and reliable method for attaching a cushion to a module housing. Thus, there is a continuous need for a cushion attachment method which provides a simple, inexpensive and yet strongly fastened assembly, without the use of a plurality of fasteners or rods and the problems associated therewith.